Plant transformation is an attractive technology for use in introducing agronomically desirable traits or characteristics into different crop plant species. Plant species are developed and/or modified to have particular desirable traits. Generally, desirable traits include, for example, improving nutritional value quality, increasing yield, conferring pest or insect resistance, disease resistance, increasing drought and stress tolerance, improving horticultural qualities (e.g., pigmentation and growth), imparting herbicide tolerance, enabling the production of industrially useful compounds and/or materials from the plant, and/or enabling the production of pharmaceuticals.
Transgenic plants comprising multiple transgenes stacked at a single genomic locus are produced via plant transformation technologies. Plant transformation technologies confer the introduction of transgenes into a plant cell, recovery of a fertile transgenic plant that contains the stably integrated copy of the transgene in the plant genome, and subsequent transgene expression via transcription and translation of the transgene(s). Thereby resulting in transgenic plants that possess desirable traits and phenotypes. Each transgene in a stack typically requires an independent promoter for gene expression within a plant, and thus multiple promoters are used in a transgene stack.
The need for co-expression of multiple transgenes for regulating the same trait frequently results in the repeated use of the same promoter to drive expression of the multiple transgenes. However, the repeated use of promoters comprising sequences that share a high level of sequence identity may lead to homology-based gene silencing (HBGS). HBGS has been observed to occur frequently in transgenic plants (Peremarti et al., 2010) when repetitive DNA sequences are used within a transgene. In addition, repeated use of similar DNA sequences in transgene constructs has proven to be challenging in Agrobacterium due to recombination and instability of the plasmid.
Described herein are maize gene regulatory elements (e.g., promoter, 5′-UTR, and 3′-UTR). Further described are constructs and methods utilizing maize regulatory elements.